Texturizing yarn, process and product

ABSTRACT

Synthetic yarn of non-circular cross-section is temporarily twisted to a less than normal extent and heat set at a temperature lower than normal to maintain original geometry and lustre.

United States Patent Nyfeler 51 Oct. 17, 1972 [5 1 TEXTURIZING YARN, PROCESS AND [56] References Cited PRODUCT UNITED STATES PATENTS m] 2:5" Nykk" 3,462,933 8/1969 Nava ..5 7/157 TS 3,069,837 12/1962 Olson ..57/l57 [73] Assignee: Heberlein Patent Corporation, New 3,316,705 5/1967 Nava ..57/157 York, NY. 3,425,893 2/1969 Sims ..57/l40 J [22] Filed: Jam 21, 3,486,320 12/1969 Mamngly et al. ..57/157 TS [21 Appl. No.: 108,607 Primary Examiner-Werner H. Schroeder Attorney-Ward, McElhannon, Brooks & Fitzpatrick [30] Foreign Application Priority Data 57] ABSTRACT Feb. 9, 1970 Switzerland ..1805/70 Synthetic yam of nomcircular cross section is ten porarily twisted to a less than normal extent and heat LS. Cl r r J, set at a temperature lower normal to maintain [5 l Illl. Clr "D028 [58] Field of Search 57/34 HS, 140.1, 157 TS,

157 MS;264/ 177 5 Claims, No Drawings TEXTURIZING YARN, PROCESS AND PRODUCT The production of highly elastic textured textile yarns by temporary high-twisting of synthetic thermoplastic multifilament yarns by means of a false-twist device and intense heat-setting in high-twisted condition is known. The optimum of twists T can be determined by means of the formula where D is the titer of the multifilament yarn expressed in denier, and the heat-setting is effected at temperatures which are situated approximately 30 to 50 C. below the melting temperature of the fiber material, i.e., at approximately 210 225 C. for polyamide and at approximately 200 220 C. for polyester. According to this method, attempts have also been made to texture multifilament yarns, the single filaments of which present a non-circular, such as e.g., a multilobal, particularly a trilobal cross-section. ln such cases, however, the lustre of the single filaments, characteristic in such yarns, has been greatly reduced by the abovementioned texturing treatment.

It is the purpose of the present invention to influence the lustre effect of a multifilament yarn consisting of single filaments with a non-circular cross-section as little as possible by the texturing process, i.e., to conserve to a great extent the original geometric form of the cross-section of the single filaments.

According to the present invention, this problem is resolved by imparting to the yarn a reduced temporary twist, and by effecting heat-setting at least 55 C. below the melting temperature of the fiber material. The temporary twist may be between 20 and 30 percent lower than calculated according to the formula where T is the number of twists and D is the denier number of the yarn, and the heat-setting treatment may be effected at a temperature situated between 55 and 70 C. below the melting point of the fiber material.

By the relatively low number of twists and heatsetting temperatures, applied in the process of the present invention, yarns with a lower elasticity and lower crimp permanence are obtained than when applying the usual texturing conditions. The reduced elasticity of the yarns, however, is precisely desirable in the manufacture of knitted articles. Furthermore, it is possible, in spite of the reduced crimp permanence, to obtain excellent properties of the articles by judicious choice of conditions in finishing.

The process of the present invention is particularly suitable for texturing multifilament yarns, the single filaments of which present a multilobal, e.g., a trilobal cross-section, and which consist of polyamides, particularly poly hexamethylene adipamide (polyamide 66). The process is, however, also suitable for yarns, the single filaments of which present other non-circular cross-sections and which consist of other synthetic thermoplastic materials, such as e.g., polyesters, particularly poly ethylene glycol terephtalate, polyacrylonitrile or polypropylene.

The process of this invention may be practiced by means of an ordinary false-twist device such as is used for the texturing of textile yarns. Examples of such devices are disclosed in US. Pat. Nos. 3,l42,953;

3,267,657; 3,373,554 and 3,518,824. In certain cases, it is also possible to operate according to the so-called twisting and separating method in which two or several yarns delivered from bobbins are mutually ply-twisted, subjected to heat-setting in this condition and separated again by continuously drawing them apart and winding up, as taught, for example, in US. Pat. Nos. 3,261,] 16; 3,261,155 and 3,261,156.

In knitting, as a rule, one yarn which has been temporarily twisted in S direction is ply-twisted with a yarn which has been temporarily twisted in Z direction and ply-yam is knitted on knitting machines. With yarns of relatively coarse titers, it is, however, also possible to knit alternatively S and Z twisted yarns on knitting machines. It is also possible to combine a yarn textured according to the present invention with a high-elastic yarn textured by the known high-twisting and intense heat-setting operation, consisting of single filaments with a circular cross-section, i.e., to assemble or plytwist them together. In this way, a combination yarn with a boucle-type effect is obtained.

The process of the present invention will be described hereinafter in detail by means of the follow ing examples:

EXAMPLE I A multifilament yarn of poly hexamethylene adipamide, denier, consisting of 20 filaments with a trilobal cross-section was temporarily high-twisted to 2300 twists per meter by means of a false-twist device, exposed to hot air of 190 C. for 0.5 seconds and cooled before entering the false-twist spindle. A yarn so-treated and false-twisted in S direction and a yarn so-treated and false-twisted in Z direction were plytwisted with turns per meter. A textured yarn was obtained, the original high lustre of which has been conserved to a great extent in spite of the texturing treatment.

EXAMPLE 2 A multifilament yarn of poly hexamethylene adipamide, denier, consisting of 34 filaments with trilobal cross-section was temporarily high-twisted to 2,000 turns per meter in S direction by means of a false-twist device and exposed to hot air of I90 C. for approximately 0.5 seconds in the high-twisted condition and cooled before entering the twist imparter of the false-twist device. A multifilament yarn of poly hexamethylene adipamide, 40 denier, consisting of l3 filaments of a circular cross-section was given a false-twist of 3,900 turns per meter in 2 direction, this yarn being passed through hot air of 220 C. in the high-twisted condition of approximately 0.5 seconds and then cooled. The two thus-textured yarns were ply-twisted with 60 turns per meter in 8 direction. A combination yarn with a boucle-like appearance was obtained, permitting the obtaining of interesting fashion effects on goods knitted therefrom.

EXAMPLE 3 A multifilament yarn of poly ethylene glycol terephtalate, denier, consisting of 44 filaments of a trilobal cross-section, was temporarily high-twisted, by means of a false-twist device, to 1,700 turns per meter and exposed to hot air of 195 C. for approximately 0.5 seconds. One half of the quantity of yarn to be processed was twisted in S direction and the other in Z direction. The thus-obtained textured yarn presents intense lustre. Yarns temporarily twisted in S and Z direction may be knitted alternatively on a knitting machine.

From the foregoing description and examples, it will be seen that l have contributed a texturing process involving the temporary high-twisting of synthetic yarns by means of a false-twist device and heat-setting of the yarn in twisted condition, the yarn being non-circular in cross-section, according to which process I conserve to a substantial extent the original geometric cross-sectional form of the yarn, and thus its original lustre.

I believe that the practice of my novel process will now be understood and that the advantages of my invention will be fully appreciated by those persons skilled in the art.

I claim:

1. Process for texturizing synthetic thermoplastic yarns consisting of single filaments of a non-circular cross-section by temporary twisting and heat-setting in the twisted condition, characterized in that a reduced temporary twist is imparted to the yarn and in that the heat-settin g operation is effected at a temperature situated at least 55 C. below the melting temperature of the filament material, wherein said reduced temporary twist is between 20 and 30 percent lower than obtained according to the formula T being the number of twists and D being the denier titer of the yarn.

2. Process according to claim 1, characterized in that the heat-setting is effected at a temperature between 55 and C. lower than the melting temperature of the fiber material.

3. Process according to claim 1, characterized in that the textured yarn is assembled with a high-elastic textured yarn obtained by temporary high-twisting and heat-setting while in the high-twisted condition.

4. Lustrous textured yarn obtained according to the process described in claim 1.

5. Process for producing lustrous textured yarns wherein a synthetic thermoplastic yarn consisting of individual filaments of non-circular cross-section is temporarily twisted to a number of twists being between 20 and 30 percent lower than obtained according to the formula T being the number of twists and D being the denier titer of the yarn and is twist-set at a temperature situated at least 55 C. below the melting temperature of the filament.

:- a s t 1: 

1. Process for texturizing synthetic thermoplastic yarns consisting of single filaments of a non-circular cross-section by temporary twisting and heat-setting in the twisted condition, characterized in that a reduced temporary twist is imparted to the yarn and in that the heat-setting operation is effected at a temperature situated at least 55* C. below the melting temperature of the filament material, wherein said reduced temporary twist is between 20 and 30 percent lower than obtained according to the formula T (275''000/D + 60) + 800, T being the number of twists and D being the denier titer of the yarn.
 2. Process according to claim 1, characterized in that the heat-setting is effected at a temperature between 55* and 70* C. lower than the melting temperature of the fiber material.
 3. Process according to claim 1, characterized in that the textured yarn is assembled with a high-elastic textured yarn obtained by temporary high-twisting and heat-setting while in the high-twisted condition.
 4. Lustrous textured yarn obtained according to the process described in claim
 1. 5. Process for producing lustrous textured yarns wherein a synthetic thermoplastic yarn consisting of individual filaments of non-circular cross-section is temporarily twisted to a number of twists being between 20 and 30 percent lower than obtained according to the formula T (275''000/D + 60) + 800, T being the number of twists and D being the denier titer of the yarn and is twist-set at a temperature situated at least 55* C. below the melting temperature of the filament. 